DAMP ON FLOOR CHIPBOARD FLOOR-

[ABCAM]

Our house is 12 years old / timber frame / brick exterior.



The ground floors, from what I can gather in order from the ground up are:

DPC
Concrete slab
Blue polythene sheet
Polystyrene sheets of insulation about 2 inches thick
Chipboard flooring


4 years ago we lifted the carpet in one room and laid a laminate floor (with appropriate underlay) over the chipboard floor – the floor looked fine)



This week we lifted the laminate and to our horror there was a large (approx 2ft by 2ft) patch of damp / black on the chipboard floor (not touching any walls, but starting about a foot into the room from the kitchen doorway)



We called a builder round who cut and lifted the affected chipboard – it was wet through its entire depth), and the polystyrene under that was also wet / stained but did not seem as bad as the chipboard. The polythene under the insulation was mildly damp to the touch in that area, but the slab underneath the sheet seems perfectly dry. There are no leaking pipes. There are no obvious signs of damp on the surface of the remaining chipboard in that room. The builder says he is fairly sure the damp has not come up from the slab through the polythene and has suggested condensation as a possibility, but is puzzled.



He has suggested leaving it a couple of weeks to see if water appears from anywhere, and if not simply lay new insulation and chipboard over the polythene in that area again



To complicate things, we are having a conservatory built adjacent to that room. The slab is down :the builders have gone for polystyrene insulation directly over the outside ground (no membrane below), with a membrane over the insulation and a concrete slab over the membrane.



We are intending using laminate flooring in the affected room and the conservatory.



As it stands I have no idea how the floors should actually have been constructed / what has caused the damp area / will it reoccur …..and am desperate for any suggestions / guidance to get some peace of mind over this.



Please help if you possibly can

 

[masona]

Have you check all service water pipe? Doesn't means the leak is where you think, could be further up and the damp area might the lowest point of the floor?

 

[ABCAM]

The builder lifted the floor/skirting back to the walls either side of the affected area and there is no sign of water coming in anywhere ?

This is causing me much concern - is it a mysterious "one-off" or could it reoccur anywhere???

 

[RigidRaider]

Read your post with interest because we have the same floors and I dread a bad leak or a flood as I hate that chipboard.

A couple of thoughts: with frequent traffic the area just inside the door could sink a little as that polystyrene sheet does compress. This would lead to water pooling in that area as someone suggests above.

Are you sure there's not some simple explanation like a pet that's in the habit of tinkling in that area, being the threshold to a room? (Though this would smell terrible) One bad flood at some time that got through the laminate and couldn't dry out?

Got kids? Line them up and threaten to confiscate Game Boys unless they admit to having flooded the place one day and cleaned up before you came home?

 

[ABCAM]

I really hope it is the result of a significant spillage since the laminate was put down 4 years ago, as that would indicate problem solved by putting down new floor to replace damaged section and it should not reoccur, but none of us (including 3 kids and 2 cats) can recall anything more than very small amounts of anything being spilt anywhere in that room.

Every time I think about it I have visions of similar patches lurking under other flooring in other rooms, spreading through the whole structure

 

[RigidRaider]

You asked the cats? Really?

Seriously though, any chance the board could have been damp when you put down the laminate? Have you seen how that stuff soaks up water?

 

[ABCAM]

The floor certainly looked OK on the surface when we lifted the carpet / put the laminate down 4 years ago
Nothing would please me more than to put this down to a one-off and never-to-be-repeated incident of spillage / trapped moisture, but I just don't see how it got there ??
Should I just leave the floors stripped down to concrete to avoid worrying about it (not a particularly attractive or warm option, but I might sleep at night??)

 

[ABCAM]

The builder who did the foundations for this house 12 years ago has just been round to have a look and is also puzzled - his opinion is that it is not coming up through the floor, and as the area is not next to a wall that a pipe leak seems unlikely (no surrounding marks)- so possibly condensation ??????

It looks like I may have to just replace the floor, relaminate and try not to think about what's going on under the surface - but what's to say it won't happen again?

 

[RigidRaider]

Can't you re-lay the boards and leave it for a couple of weeks before finishing off?

(We've been walking around on chipboard for 2 years because we can't afford to carpet!)

I'm sure your board was wet before the laminate went down. Try an experiment: take a piece of chipboard, pour water on it, leave 5 minutes, dry off then wrap in a plastic bag. Then come back and open it a week later. I bet you'll find a mess.

 

[big-all]

ok my thought on this one

was the laminate immediatly above the " dammaged patch" affected at all!!!
if no noticable damage [swelling joints and edges] this would suggest the top membrane was intact and the water hasnt been a spill on the top
the fact the dammage is only covering about 2' of floor suggest a relatively small amount of water perhaps 30% of a cup
it may or may not have come through from the concrete as residual moisture thats trapped not an important point as it should now be at a stable level
the moisture atracted to the wood is absorbed like a sponge and cant evaporate as its surounded by plastic that keeps the floor sweating

so in summary if all membrains are opened and the air is allowed to flow the trapped moisture is allowed to evaporate the problem will dissapear

 

[ABCAM]

rigid raider / big all

The laminate seemed absolutely fine when we lifted it (no obvious damp / marking along the joints, just a bit damp where it was touching the wet chipboard.)

I'm not sure how it could have been residual moisture in the concrete slab : there is a membrane above the concrete, and the house had already been built / that room carpeted for7 or 8 years before we put the laminate down ?

You both seem very reassuring however, that it's unlikely to reoccur - when I call the builder back in to repair the gap in the floor, I may ask him to lift the rest of the chipboard / polystyrene in that room first to check for any other "hidden" spots, then put down insulation and chipboard on the membrane as before. We won't be putiing new laminate down for a little while

Thank you for taking the time to give me your thoughts on this (Logic tells me I should now forget about it and trust the structure of the house - 2am demons can't quite let it go!!)

 

[RigidRaider]

Yes, tell yourself to stop worrying - there are much worse things that can happen in a house! After all, did the damp patch actually DO any harm? A bit of wood was damp, plastic prevented it from drying out and some mould was happy to grow there for a few years.

I own a 20 year old Land Rover, which give reliable service. However it does make the occasional funny noise. Land Rover's official doctrine on noise is: "keep driving until it becomes unbearable for the operator. At this point, consider an overhaul". Maybe we should be as pragmatic about our houses!

 

[ModernMaterials]

Pour some water tentatively over your stain and see if it goes anywhere else.

If it doesn't, I would be fairly confident that it came from above.

If it came from above you should question the kids/cats again...